Process of treating asbestus



UNITED STATES PATENT OFFICE.

ISAIAH II. ROBERTS, OF BROOKLYN, ASSIGNOR OF ONE-HALF TO THOMAS II. MCGRAIV, OF POUGHKEEPSIE, NEW YORK.

PROCESS OF TREATING ASBESTUS.

SPECIFICATION forming part of Letters Patent No. 442,335, dated December 9, 1890. Application filed March 14, 1889= Renewed October 22, 1890. Serial No. 368,973. (No specimens.)

To all whom it may concern:

Be it known that I, ISAIAH L. ROBERTS, a citizen of the United States, residing at Brooklyn, in the county of Kings and State of New York, have invented a new and useful Process of Treating Asbestus, of which the following is a specification.

This invention is a process of treating asbestus designed for use in the manufacture 1 or composition of diaphragms for galvanic batteries, electrolytic cells, and similar purposes. Asbestus board, as it comes in the market, is not suited for these purposes, for it contains various constituent compounds which, particularly in electrolytic cells, are

2o insula ing bubbles of gas, loses to a greater or less extent its conducting and electrolytic qualities. The process which forms the subject of my present invention is designed to free the asbestus or asbestus board from these soluble or decomposable elements, so that when made in or used as a diaphragm it will be a good conductor or electrolyte, and for this purpose I treat the asbestus as follows: I first subject it to the action of an acidsuch 0 as sulphuric or muriatic acid, and preferably the latter-until the objectionable elements are neutralized or partly removed and partly rendered soluble, and then washing it well in fresh Water. I generally repeat this process 5 one or more times and finally subject the mass to pressure.

I find it convenient to make the asbestus up into the form of a diaphragm first and then treat it, and in carrying out the invention in this way I proceed as follows:

I cut out two pieces of asbestus board of the desired dimensions and lay them on opposite sides of a piece of asbestus cloth of about the same shape. I then sew or fasten them up in a covering or bag of cotton cloth or the like. I then expose the whole for about twenty-four hours to the action of muriat-ic acid of about 12 Baum. I then squeeze or roll them and again treat them with the acid. I then roll and knead the bag in fresh water until the salts or soluble portions resulting from the action of the acid are thoroughly washed out. The bag is finally subjected to pressure to free it of surplus moisture and gas and to reduce its bulk.

\Vhat I claim is- 1. The process of preparing asbestus for electrical diaphragms, which consists in exposing asbestus board or cloth to the action of an acid, then washing out the soluble parts, and then compressing it, as set forth.

2. The process of preparing asbestus for electrical diaphragms by the removal or neutralization of its soluble or decomposable constituents, which consists in exposing it to the action of dilute muriatic acid, washing it with water, and compressing it, as herein set forth.

ISAIAH L. ROBERTS. "itnesses:

RoBr. F. GAYLORD, PARKER W. PAGE. 

